What is the structure of the intervertebral disc, and what causes lumbar disc herniation?

In general, the structure of the intervertebral disc consists of the annulus fibrosus and nucleus pulposus. Causes of lumbar disc herniation include natural degenerative changes, incorrect posture, sustained pressure and loading, trauma, osteoporosis, and others. If discomfort occurs, it is recommended to seek medical attention promptly for treatment. A detailed analysis is as follows:

1. Structure of the Intervertebral Disc

The intervertebral disc is a cartilaginous structure located between the lumbar vertebrae, serving as a cushion and support. It consists of two main components: the annulus fibrosus and the nucleus pulposus. The annulus fibrosus is the outer portion of the disc, composed of concentric layers of fibrocartilaginous tissue. Its primary function is to provide strength and stability to the disc, protecting the inner nucleus pulposus. The nucleus pulposus is the inner central part of the disc, primarily composed of water and collagen. Its main role is to absorb and distribute mechanical stress from the spine, providing cushioning and support.

2. Causes

2.1 Natural Degenerative Changes
With aging, intervertebral discs undergo degeneration—gradual deterioration in their structure and function. This is one of the most common causes of lumbar disc herniation. It is advisable to consume protein-rich foods such as fish, eggs, and chicken regularly, which may help prevent lumbar disc herniation.

2.2 Incorrect Posture
Poor posture and body positioning, such as prolonged head-down positions, bending forward, or twisting, can place additional pressure and stress on the intervertebral discs. These improper postures may accelerate disc degeneration and injury, increasing the risk of disc herniation. If maintaining correct posture is difficult, consider using supportive devices such as lumbar cushions or spinal support belts. These aids can help maintain proper alignment and reduce stress on the lumbar spine.

2.3 Sustained Pressure and Load
Long-term heavy lifting and repetitive physical activities increase stress on the lumbar spine. When the weight exceeds the capacity of the lumbar muscles and discs, excessive pressure can cause the disc to bulge or protrude, leading to lumbar disc herniation. It is recommended to use appropriate tools and equipment to reduce strain, such as hand trucks or lifting straps. Whenever possible, share the load with others to minimize individual stress.

2.4 Trauma
Severe injuries such as car accidents, falls, or sports-related trauma may result in vertebral fractures or dislocations. Such injuries can exert excessive pressure on the intervertebral discs, potentially causing lumbar disc herniation. Medications such as celecoxib capsules, meloxicam tablets, or ibuprofen sustained-release capsules may be used under medical guidance for treatment.

2.5 Osteoporosis
Osteoporosis is a bone disorder characterized by reduced bone mass and density. As bone density decreases, bones become fragile and prone to fracture. The lumbar vertebrae are commonly affected by osteoporosis; decreased bone density increases vertebral fragility, thereby raising the risk of lumbar disc herniation. Under medical supervision, medications such as glucosamine sulfate capsules, glucosamine hydrochloride tablets, or calcium carbonate D3 granules may be prescribed for management.

In daily life, consuming foods rich in calcium and vitamin D—such as cod liver oil, milk, and cheese—can help reduce the risk of lumbar disc herniation.